The present invention relates to a coaxial cavity resonator having a reduced dimension with a high Q value in the ultrahigh frequency band (0.3 to 3 GHz).
Most of the coaxial cavity resonator of the UHF range are of the lumped constant LC type, or of the halfwave or quarter-wave coaxial type. The lumped constant type has an advantage of compactness, but it has a disadvantage of a high loss, while the halfwave or quarter-wave type has an advantage of low loss, but it has a disadvantage of greater dimension than the former. Therefore, the compactness and low loss characteristics of the prior art coaxial cavity resonator are not satisfactory.
Although it is known that the provision of a dielectric material of a high dielectric constant with a low dielectric loss in a space between the inner and outer conductors of the coaxial cavity resonator could result in a resonator having a reduced dimension and an increase in the Q value, the present invention eliminates the use of such dielectric material for the purposes of solving the aforesaid problems.